The role of the mid-dorsolateral prefrontal cortex in working memory

Epidemiological studies have reported that consumption of dairy products rich in β-lactolin is beneficial for cognitive decline among elderly individuals. Although previous studies have shown that β-lactolin supplementation improves memory function and attention in healthy adults, the mechanism through which β-lactolin affects human brain function has yet to be elucidated. This placebo-controlled randomized double-blind study therefore examined the effects of β-lactolin on human regional cerebral blood flow (rCBF) using near-infrared spectroscopy (NIRS) according to the Consolidated Standards of Reporting Trials guidelines. A total of 114 healthy participants aged between 50 and 75 years with relatively low cognition were randomly allocated into the β-lactolin or placebo groups (n = 57 for both groups) and received supplementation for 6 weeks. After the 6 weeks of supplementation, total hemoglobin during cognitive tasks (Kraepelin and 2-back tasks) was measured using two-channel NIRS to determine rCBF. Accordingly, the β-lactolin group had significantly higher changes in total hemoglobin at the left dorsolateral prefrontal cortex (DLPFC) area measured using the left-side channel during the 2-back tasks (p = 0.027) compared to the placebo group. The present study suggests that β-lactolin supplementation increases rCBF and DLPFC activity during working memory tasks.

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Functional role of dorsolateral prefrontal cortex in the modulation of cognitive bias

Psychophysiology ◽

10.1111/psyp.13894 ◽

2021 ◽

Author(s):

Xue Xia ◽

Yansong Li ◽

Yanqiu Wang ◽

Jing Xia ◽

Yitong Lin ◽

...

Keyword(s):

Prefrontal Cortex ◽

Cognitive Bias ◽

Functional Role ◽

Dorsolateral Prefrontal Cortex ◽

Dorsolateral Prefrontal

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Working memory requirements influence the strength of visual motion direction representations in dorsolateral prefrontal cortex neurons

Journal of Vision ◽

10.1167/12.9.1270 ◽

2012 ◽

Vol 12 (9) ◽

pp. 1270-1270

Author(s):

D. Mendoza-Halliday ◽

J. Martinez-Trujillo

Keyword(s):

Working Memory ◽

Prefrontal Cortex ◽

Dorsolateral Prefrontal Cortex ◽

Visual Motion ◽

Motion Direction ◽

Dorsolateral Prefrontal

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Prefrontal and Parietal Attractor Networks Mediate Working Memory Judgments

10.1101/2020.06.01.128173 ◽

2020 ◽

Author(s):

Sihai Li ◽

Christos Constantinidis ◽

Xue-Lian Qi

Keyword(s):

Working Memory ◽

Prefrontal Cortex ◽

Dorsolateral Prefrontal Cortex ◽

Critical Role ◽

Memory Task ◽

Delayed Response ◽

Persistent Activity ◽

Neural Basis ◽

Brain Areas ◽

Dorsolateral Prefrontal

ABSTRACTThe dorsolateral prefrontal cortex plays a critical role in spatial working memory and its activity predicts behavioral responses in delayed response tasks. Here we addressed whether this predictive ability extends to categorical judgments based on information retained in working memory, and is present in other brain areas. We trained monkeys in a novel, Match-Stay, Nonmatch-Go task, which required them to observe two stimuli presented in sequence with an intervening delay period between them. If the two stimuli were different, the monkeys had to saccade to the location of the second stimulus; if they were the same, they held fixation. Neurophysiological recordings were performed in areas 8a and 46 of the dlPFC and 7a and lateral intraparietal cortex (LIP) of the PPC. We hypothesized that random drifts causing the peak activity of the network to move away from the first stimulus location and towards the location of the second stimulus would result in categorical errors. Indeed, for both areas, when the first stimulus appeared in a neuron’s preferred location, the neuron showed significantly higher firing rates in correct than in error trials. When the first stimulus appeared at a nonpreferred location and the second stimulus at a preferred, activity in error trials was higher than in correct. The results indicate that the activity of both dlPFC and PPC neurons is predictive of categorical judgments of information maintained in working memory, and the magnitude of neuronal firing rate deviations is revealing of the contents of working memory as it determines performance.SIGNIFICANCE STATEMENTThe neural basis of working memory and the areas mediating this function is a topic of controversy. Persistent activity in the prefrontal cortex has traditionally been thought to be the neural correlate of working memory, however recent studies have proposed alternative mechanisms and brain areas. Here we show that persistent activity in both the dorsolateral prefrontal cortex and posterior parietal cortex predicts behavior in a working memory task that requires a categorical judgement. Our results offer support to the idea that a network of neurons in both areas act as an attractor network that maintains information in working memory, which informs behavior.

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Reducing future fears by suppressing the brain mechanisms underlying episodic simulation

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1606604114 ◽

2016 ◽

Vol 113 (52) ◽

pp. E8492-E8501 ◽

Cited By ~ 21

Author(s):

Roland G. Benoit ◽

Daniel J. Davies ◽

Michael C. Anderson

Keyword(s):

Prefrontal Cortex ◽

Dorsolateral Prefrontal Cortex ◽

Ventromedial Prefrontal Cortex ◽

Episodic Simulation ◽

Dorsolateral Prefrontal ◽

Future Events ◽

The Right ◽

Development Of Anxiety ◽

The Brain

Imagining future events conveys adaptive benefits, yet recurrent simulations of feared situations may help to maintain anxiety. In two studies, we tested the hypothesis that people can attenuate future fears by suppressing anticipatory simulations of dreaded events. Participants repeatedly imagined upsetting episodes that they feared might happen to them and suppressed imaginings of other such events. Suppressing imagination engaged the right dorsolateral prefrontal cortex, which modulated activation in the hippocampus and in the ventromedial prefrontal cortex (vmPFC). Consistent with the role of the vmPFC in providing access to details that are typical for an event, stronger inhibition of this region was associated with greater forgetting of such details. Suppression further hindered participants’ ability to later freely envision suppressed episodes. Critically, it also reduced feelings of apprehensiveness about the feared scenario, and individuals who were particularly successful at down-regulating fears were also less trait-anxious. Attenuating apprehensiveness by suppressing simulations of feared events may thus be an effective coping strategy, suggesting that a deficiency in this mechanism could contribute to the development of anxiety.

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